Scrapy: need to iterate over items and pages

I have a list of instagram in a .txt file.

This is the URL which i have to scrape: https://brandfollowers.io/kol/all-post?uid=$INSTAGRAM$&page_num=$PAGENUMBER$(note i put $INSTAGRAM$ and $PAGENUMBER$ where i need to change variables)

For example, in this URL https://brandfollowers.io/kol/all-post?uid=philipppleinofficial&page_num=1

Im very new at this but actually i managed to work on take all items in page 1 for every instagram in list. However, i cant iterate over all pages from every instagram.

Could you please give me some tip? Im very new in this topic.

This is what i got right know:

# -*- coding: utf-8 -*-
import scrapy
import json


class ContenidoSpider(scrapy.Spider):
    name = 'BACKUP_contenido'
    allowed_domains = ['brandfollowers.io']
    start_urls = ['http://brandfollowers.io/']
    base_url = 'http://brandfollowers.io/kol/all-post?uid='


    def parse(self, response):

        FILE = open('list.txt', 'r').readlines()
        instagrams = []


        for lines in FILE:
            new_line = lines.replace('https://www.instagram.com/', '')
            instagrams.append(new_line)

        for instagram in instagrams:
            posts_url = self.base_url + instagram

            yield scrapy.Request(posts_url, callback=self.parse_json)

    def parse_json(self, response):
        current_page = 0
        pagesize = 6
        json_response = json.loads(response.text)
        path = json_response["data"]["models"]

        while current_page < pagesize:

            brand = path[current_page]["author"]["platform_unique_id"]
            date = path[current_page]["platform_create_time"]
            comments = path[current_page]["comment_count"]
            likes = path[current_page]["like_count"]
            engagement_rate = path[current_page]["share_count"]
            description = path[current_page]["description"]
            url_post = path[current_page]["post_url"]
            picture_link = path[current_page]["picture_link"]


            yield {

                'BRAND': brand,
                'DATE': date,
                'COMMENTS': comments,
                'LIKES': likes,
                'ENGAGEMENT RATE': engagement_rate,
                'DESCRIPTION': description,
                'URL': url_post,
                'PICTURE LINK': picture_link,

            }

            current_page += 1